Yep, I can put lights inside transparent objects, but as you've found out, I had trouble varying the softness of the shadows; if the size of the soft DRT shadows is bigger than the transparent object the light's inside, I got all sorts of freaky effects, none of which were particularly pleasing.... I'm looking forward to seeing some posts! (It also looks like I'm going to have to upgrade to RDS 5.5, finally.... Hoping to find a cheap close-out copy somewhere....)